CVE-2005-0519 in FTP Server
Summary
by MITRE
ArGoSoft FTP Server before 1.4.2.7 allows remote attackers to read arbitrary files by uploading a ZIP file containing a shortcut (.LNK) file, using SITE UNZIP to extract the .LNK file onto the server, then accessing the file, a different vulnerability than CVE-2005-0520.
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Analysis
by VulDB Data Team • 07/04/2025
The ArGoSoft FTP Server vulnerability CVE-2005-0519 represents a critical path traversal flaw that enables remote attackers to access arbitrary files on the server through a sophisticated multi-stage attack vector. This vulnerability specifically affects versions prior to 1.4.2.7 and exploits the server's handling of compressed archive files, particularly ZIP archives containing malicious shortcut files. The attack leverages the SITE UNZIP command functionality to extract malicious .LNK files onto the server filesystem, creating a pathway for unauthorized file access that bypasses normal security controls.
The technical exploitation mechanism involves uploading a specially crafted ZIP file containing a Windows shortcut (.LNK) file that points to system files outside the intended directory structure. When the server processes this ZIP file using the SITE UNZIP command, the .LNK file gets extracted to the server's filesystem, often in a location where it can be accessed through subsequent FTP commands. This technique exploits a fundamental flaw in how the server handles file extraction and path resolution, allowing attackers to create symbolic links or hard links that point to sensitive system files such as password databases, configuration files, or other restricted resources.
This vulnerability operates under the broader category of path traversal attacks and falls under CWE-22 Path Traversal and CWE-23 Relative Path Traversal, representing a classic example of how archive extraction functions can be abused to circumvent access controls. The attack chain demonstrates the principle of privilege escalation through file system manipulation, where a simple FTP upload operation can lead to complete system compromise. The vulnerability's classification aligns with ATT&CK technique T1078 Valid Accounts and T1566 Phishing, as it enables attackers to gain access to sensitive files that would normally require elevated privileges or direct system access.
The operational impact of this vulnerability extends beyond simple file reading, as it can potentially expose sensitive information including user credentials, system configurations, and application data. Attackers can leverage this vulnerability to gain insights into the server's internal structure, identify other potential attack vectors, and establish persistent access to the compromised system. The vulnerability's persistence stems from the fact that extracted .LNK files can remain accessible on the server filesystem, providing attackers with ongoing access to the compromised resources. Organizations using affected versions of ArGoSoft FTP Server face significant risk of data breaches and system compromise, particularly in environments where FTP servers handle sensitive or confidential information.
Mitigation strategies for CVE-2005-0519 require immediate patching of affected systems to version 1.4.2.7 or later, which addresses the flawed archive extraction logic and implements proper path validation. Network administrators should also implement restrictive FTP access controls, disable unnecessary commands such as SITE UNZIP, and monitor FTP server logs for suspicious file upload patterns. Additional protective measures include implementing network segmentation to isolate FTP servers, deploying intrusion detection systems to monitor for exploitation attempts, and establishing regular security audits of FTP server configurations. Organizations should also consider implementing file type validation and content scanning for uploaded files to prevent the execution of malicious shortcuts or symbolic links that could exploit similar vulnerabilities in other applications.